Self-standing Co2.4Sn0.6O4 nano rods as high performance anode materials for sodium-ion battery and investigation on its reaction mechanism

The self-standing nanorod Co2.4Sn0.6O4 is synthesized as a high-performance anode material in search of high capacity and stable anode materials for sodium-ion batteries. The Co2.4Sn0.6O4 nanorod exhibits a high reversible capacity of 576 mAh g-1 at a current density of 80 mA g-1 and shows excellent high-rate capability. The X-ray absorption spectroscopy study reveals the mechanisms of charge storage reaction and improved cycling performance of Co2.4Sn0.6O4. A partially limited conversion reaction of Co- and Sn-oxide during the cycling effectively regulate the irreversible capacity loss over the cycling that is commonly observed from the conversion and alloying reaction-based anode materials. Furthermore, Co2.4Sn0.6O4 also exhibits superior sodium-ion full cell performance when coupled with a NaNi2/3Bi1/3O2 cathode, demonstrating an energy density of 262 Wh kg- 1.